This document provides information on the genus Yersinia including:
1) Yersinia pestis causes bubonic plague in humans and some animal species. Y. pseudotuberculosis and Y. enterocolitica can cause enteric diseases in humans and animals.
2) Yersinia species are facultative anaerobes that can grow at temperatures from 5-42°C. They are classified as Enterobacteriaceae.
3) Yersinia infections in animals include enteric disease in young ruminants and septicaemia in caged birds. Human infections include bubonic plague, as well as enteric diseases from Y. enterocolitica and Y. pseudotuberculosis
Microbiology of E coli giving basic of Escherichia coli, its morphology, cultural and biochemical characteristics, Antigenic character, pathogenesis, laboratory diagnosis, prevention and control
Microbiology of E coli giving basic of Escherichia coli, its morphology, cultural and biochemical characteristics, Antigenic character, pathogenesis, laboratory diagnosis, prevention and control
Haemophilus is the name of a group of bacteria. There are several types of Haemophilus. They can cause different types of illnesses involving breathing, bones and joints, and the nervous system. One common type, Hib (Haemophilus influenzae type b), causes serious disease. It usually strikes children under 5 years old
The genus Shigella exclusively infects human intestine.
Shigella dysenteriae is the causative agent of bacillary dysentery or shigellosis in humans.
It is a diarrheal illness which is characterized by frequent passage of blood stained mucopurulent stools.
The four important species of the genus Shigella are:
Shigella dysenteriae
Shigella flexneri
Shigella sonnei
Shigella boydii.
A picornavirus is a virus belonging to the family Picornaviridae, a family of viruses in the order Picornavirales. Vertebrates, including humans, serve as natural hosts. Picornaviruses are nonenveloped viruses that represent a large family of small, cytoplasmic, plus-strand RNA viruses with a 30-nm icosahedral capsid.
Haemophilus is the name of a group of bacteria. There are several types of Haemophilus. They can cause different types of illnesses involving breathing, bones and joints, and the nervous system. One common type, Hib (Haemophilus influenzae type b), causes serious disease. It usually strikes children under 5 years old
The genus Shigella exclusively infects human intestine.
Shigella dysenteriae is the causative agent of bacillary dysentery or shigellosis in humans.
It is a diarrheal illness which is characterized by frequent passage of blood stained mucopurulent stools.
The four important species of the genus Shigella are:
Shigella dysenteriae
Shigella flexneri
Shigella sonnei
Shigella boydii.
A picornavirus is a virus belonging to the family Picornaviridae, a family of viruses in the order Picornavirales. Vertebrates, including humans, serve as natural hosts. Picornaviruses are nonenveloped viruses that represent a large family of small, cytoplasmic, plus-strand RNA viruses with a 30-nm icosahedral capsid.
A presentation about the microorganism yersinia entercolitica, including intro, history, types, cause of pathogenicity, health problems it causes, outbreaks, control measures etc
Toxoplasmosis is considered one of the neglected parasitic infections of the United States, a group of five parasitic diseases that have been targeted by CDC for public health action.Q fever is a disease caused by the bacteria Coxiella burnetii. This bacteria naturally infects some animals, such as goats, sheep, and cattle. C. burnetii bacteria are found in the birth products (i.e. placenta, amniotic fluid), urine, feces, and milk of infected animals.
In the ppt. Babesia is explained along-with its species, its life cycle, treatment and prevention. It explains Babesia and answers questions like, What is Babesiosis? What are the species of Babesia? What is the host of Babesia? How they are spread across the globe? What are their mode of reproduction? What is their life cycle? What is the historical background of Babesiosis? How scientist named the disease? What is the morphology of Babesia? What are the stages of Life cycle of Babesia? How Babesiosis is treated? How can we prevent Babesiosis?
Tick-borne parasitic infections are serious problem in the world as the population of ticks is increasing with people building homes in areas where ticks and their host live. Ticks are second to mosquitoes as an excellent vector for vector-borne diseases. There are only two known tick-borne parasitic infections: Babesiosis and Theileriosis. Babesiosis is due to the tick-borne parasites of the Babesia protozoa genus while Theileriosis is caused by Theilerias species which are obligate protozoan parasites. They are both transmitted by the Ixodid ticks. The symptoms of the infection includes lacrimation, nasal discharge, muscle pains etc. Tick-borne parasitic diseases can be prevented by avoiding places where ticks often live and also by using insect repellents.
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one of the best power point about plague(black death) , its easy for understand and prepared with a good quality which will be useful for all students and doctors that want w prepare a presentation
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
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Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
micro teaching on communication m.sc nursing.pdfAnurag Sharma
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Anti ulcer drugs and their Advance pharmacology ||
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Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...
Genus Yersinia
1. Genus Yersinia
Dr Ravi Kant Agrawal, MVSc, PhD
Senior Scientist (Veterinary Microbiology)
Food Microbiology Laboratory
Division of Livestock Products Technology
ICAR-Indian Veterinary Research Institute
Izatnagar 243122 (UP) India
2. The causative agent of plague, Yersinia pestis, was discovered by the
French/Swiss microbiologist A.E.J. Yersin and Kitasato Shibasaburō
Japanese bacteriologist in Hong Kong in 1894.
It was formerly described as Pasteurella pestis (known trivially as the
plague-bacillus by Lehmann and Neumann in 1896.
In 1944, van Loghem reclassified the species P. pestis and P.
rondentium into a new genus, Yersinia.
Ukrainian scientists D. Samoilovich, D. Zabolotny and others
contributed greatly to the study of the mechanisms of its
transmission.
The French microbiologists G. Girard and T. Robic obtained a live
vaccine from the attenuated EV strain.
Bubonic plague, caused by Y. pestis, is an ancient disease that has
killed millions of people over the centuries.
It is believed to have killed more than 100 million persons in an
epidemic in the sixth century.
Another epidemic in the 14th century killed one fourth of the
European population.
The London plague in 1665 killed more than 70,000 persons.
In 1893, an epidemic began in Hong Kong and spread to India where
more than 10 million individuals died over a 20-year period.
Historical Aspect
3. Biochemical and growth characteristics
• Are Gram negative Enterobacteriaceae member
• Previously classified in Pasteurellaceae family.
• Based on DNA similarities with E. coli, Y. pestis is now part of
Enterobacteriaceae family
• Short coccobacillary, ovoid or rod shaped, pleomorphic Gram
negative rods.
• Exhibit bipolar staining in Geimsa stained smears from animal tissues.
• Yersinia species are non-lactose fermenters
• Motile with the exception of Y. pestis.
• Are catalase positive, oxidase negative, Indole -ve, ONPG +ve, Urease
+ve except Y. pestis
• Aerobic/facultative anaerobic or Microaerophilic.
• Most have animals as their natural hosts, but they can produce
serious disease in humans.
• Grow on ordinary media, however, growth is slower than other
Enterobacteriaceae members
• Wide temperature range (5-42 C)
• Best growth temp. 25-30C
• Yersinia has the ability to not only survive, but also to actively
proliferate at temperatures as low as 1–4°C (e.g., on cut salads and
other food products in a refrigerator).
4. Classification
11 named species in genus 3 are
human and animal pathogens
Y. pestis, Y. pseudotuberculosis, Y.
enterocolitica
Y. pestis- plague
Y. pseudotuberculosis - human
diarrhoeal diseases (rarely infect
humans)
Y. enterocolitica is the cause of 1 – 3%
of diarrhea cases caused by bacteria
Y. ruckeri causes perioral
haemorrhagic imflammation in some
species of fish.
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Enterobacteriales
Family: Yersiniaceae
Genus: Yersinia (van Loghem, 1944)
Species
•Y. aldovae
yb
•Y. aleksiciae
•Y. bercovieri
yb
•Y. enterocolitica
yb
Y. enterocolitica subsp.
enterocoliticaYersinia enterocolitica subsp. palearctica
•Y. entomophaga
•Y. frederiksenii
yb
•Y. intermedia
yb
•Y. kristensenii
yb
•Y. massiliensis
yb
•Y. mollaretii
yb
•Y. nurmii
•Y. pekkanenii
•Y. pestis
yb
•Y. philomiragia
•Y. pseudotuberculosis
yb
Y. pseudotuberculosis subsp.
pestisY. pseudotuberculosis subsp. pseudotuberculosis
•Y. rohdei
yb
•Y. ruckeri
yb
•Y. similis
5. Serotyping and biotyping methods used for identifying pathogenic
yersiniae.
Of the ten serotypes of Y. pseudotuberculosis, serotypes I , II and III contain
the majority of pathogenic isolates.
There are five biotypes and more than 50 serotypes of Y. enterocolitica.
Somatic antigens 2, 3, 5, 8 and 9 are present in isolates from clinical
infections caused by this species.
Serotype 0:9 is of particular importance because it shares common
antigens with BruceIla species and it may induce false-positive reactions in
brucella agglutination tests.
Yersinia pseudotuberculosis and Y. enterocolitica are found in the intestinal
tract of a wide range of wild mammals, birds and domestic animals.
All these animals may be reservoirs of infection.
Many avian species may act as amplifier hosts and may also transfer the
organisms mechanically.
Both organisms can grow in a wide temperature range (5 to 42°C) and
survive for long periods in cool wet conditions.
In endemic areas, wild rodents are important reservoirs of Y. pestis.
Fleas, especially Xenopsylla cheopis, the Oriental rat flea, transmit the
infection to man and other animals.
6. Pathogenicity
Pathogenic yersiniae are facultative intracellular organisms which possess
plasmid and chromosomal encoded virulence factors, many of which are
required for survival and multiplication in macrophages.
Yersinia pseudotuberculosis and Y. enterocolitica are less virulent than Y. pestis
and rarely produce generalized infections.
The pathogenic mechanisms in enteric disease caused by Y. enterocolitica and Y.
pseudotuberculosis are incompletely understood.
It is probable that both organisms gain entry to the mucosa through M cells of
Peyer's patches.
Adhesion to and subsequent invasion through these cells are facilitated by
factors such as invasin and adhesion-invasion proteins which have an affinity for
integrins on cell surfaces.
Once in the mucosa, the bacteria are engulfed by macrophages in which they
survive and are transported to the mesenteric lymph nodes (Brubaker, 1991).
Replication in the nodes follows with the development of necrotic lesions and
neutrophil infiltration.
Survival of Y. pseudotuberculosis and Y. enterocoiitica is enhanced by
antiphagocytic proteins secreted by the organisms which interfere with the
normal functioning of neutrophils in the host.
Yersinia pestis is more invasive than Y. pseudotubercuIosis and Y. enterocolitica
and possesses additional virulence factors include an antiphagocytic protein
capsule (Fraction 1) and a pIasminogen activator which aids systemic spread.
Endotoxin, with properties similar to the endotoxin produced by other members
of the Enterobacteriaceae, also contributes to the pathogenesis of disease.
9. Clinical Infections
Yersinia pseudotuberculosis causes enteric infections, in a wide
variety of wild and domestic animals which are often subclinical.
The septicaemic form of disease, known as pseudotuberculosis,
can occur in laboratory rodents and aviary birds.
Sporadic abortions caused by Y. pseudotuberculosis have been
reported in cattle, sheep and goats.
Wild and domestic animals may act as reservoirs of Yersinia
enterocolitica which is primarily a human enteric pathogen.
The pig is the natural reservoir for Y. enterocolitica serotype 03
biotype 4, which is an important pathogen in humans.
Rare cases of enteric disease, precipitated by stress, may be
encountered in pigs, farmed deer, goats and lambs.
Yersinia enterocolitica has been implicated in sporadic ovine
abortions.
Yersinia pestis, the cause of human bubonic plague (black death),
can infect both dogs and cats in endemic areas.
Cats, which are particularly susceptible, may be a source of
infection for owners and attending veterinarians.
10. Pathogenesis and Clinical Findings
Yersinia enterocolitica and Y. pseudotuberculosis
• An inoculum of 108 – 109 yersiniae must enter the alimentary tract to
produce infection
• During IP of 5 – 10 days, yersiniae multiply in the gut mucosa
particularly the ileum
• Leads to inflammation and ulceration and leukocytes appear in feces
• The process may extend to mesenteric lymph nodes and rarely to
bacteremia
• Early symptoms include fever, abdominal pain, and diarrhoea
• Diarrhoea ranges from watery to bloody and may be due to an
enterotoxin or to invasion of the mucosa
• At times abdominal pain is severe and located in the right lower
quadrant suggesting appendicitis (Pseudoappendicitis)
• 1 to 2 weeks after onset some patients develop arthalgia, arthritis and
erythema nodosum suggesting immunologic reaction to the infection
• Very rarely, it produces pneumonia, meningitis or sepsis; in most
cases, it is self-limited
11. Enteric yersiniosis
Enteritis caused by Y. pseudoruberculosis is relatively common in
young farmed deer in New Zealand and Australia.
Outbreaks of the disease have been reported also in buffaloes in
Brazil.
Enteric disease has been reported in sheep, goats and cattle under
one year of age.
Subclinical infection in many species is common and clinical disease
may be precipitated in the winter months by stress factors such as
poor nutrition, weaning, transportation and cold wet conditions.
There may be prolonged survival of Y. pseudotuberculosis on pasture
in cold wet weather, facilitating faecal-oral transmission.
Enteritis in young deer and lambs is characterized by profuse watery
diarrhoea, sometimes blood-stained, which may be rapidly fatal if
untreated.
The luminal contents of the small and large intestine are watery and
mucosal hyperaemia is evident at postmortem examination.
Severely affected animals may show mucosal ulceration.
The mesenteric lymph nodes are often enlarged and oedematous and
scattered pale necrotic foci may be present in the liver.
A clinically similar but less severe enterocolitis caused by Y.
enterocolitica has been described in young ruminants.
12. Septicaemic yersiniosis
Septicaemia, caused by Y. pseudotuberculosis occurs in birds
kept in cages or aviaries.
It is presumed that infection is acquired through contact with
the faeces of wild birds or rodents, or through the feeding of
contaminated leafy plants.
In aviaries, overcrowding may predispose to the development
of disease.
Infected birds may die suddenly.
Some may display ruffling of feathers and listlessness shortly
before death.
Pin-point white necrotic foci are present in the Iiver at
postmortem.
Confirmation is based on the isolation and identification of Y.
pseudotuberculosis from the liver and other internal organs.
Treatment is seldom feasible due to the acute nature of the
disease.
Control should be aimed at preventing faecal contamination of
food and water by wild birds and rodents.
13. Pseudotuberculosis in Laboratory animals
Infection with Y. pseudotuberculosis in colonies
of G. pigs or rodents is usually introduced
through faecal contamination of food by wild
rodents.
Diarrhoea and gradual weight loss leading to
emaciation and death are the signs most often
observed in affected animals.
Some animals may die suddenly from
septicaemia.
At postmortem examination, numerous white
necrotic lesions are present in the liver.
Affected mesenteric lymph nodes are enlarged
and may show caseous necrosis.
Treatment is usually not desirable because some
animals in the colony may become carriers and
the organism is zoonotic.
Depopulation, disinfection and restocking are
the preferred control measures.
Exclusion of wild rodents is an essential step in
preventing infection with Y. pseudotuberculosis.
14. Diagnosis
The species and age group affected, especially
during cold wet spells of weather, may suggest
yersiniosis.
HistoIogical examination of intestinal lesions may
reveal clusters of organisms in microabscesses
within the mucosa.
Confirmation requires isolation and identification
of Y. pseudutuberculosis or Y. entercolitica.
Samples from tissues can be plated directly onto
blood and MacConkey agars and incubated
aerobically at 37°C for up to 72 hours.
Faecal samples may be plated directly onto special
selective media.
A cold enrichment procedure may facilitate
recovery of yersiniae from faeces especially if they
are present in low numbers.
A 5% suspension of faeces in PBS, held at 4°C for 3-4
weeks, is subcultured weekly onto MacConkey
agar.
Serotyping may be necessary to establish whether
the isolates belong to known pathogenic
serotypes.
15. Differentiation of Yersinia Species
Species
Carbohydrate fermentation
Productionof
Hydrogen
sulphide
adonitol
arabinose
arabitol
arbutin
sorbitol
xylose
Y. pestis – + – – + + +
Y. pseudotuber-
culosis
+ + – + – – –
Y. enterocolitica – + – + + + +
16. Some diagnostic signs differentiating the bacteria of
plague from those of pseudotuberculosis in rodents
Yersinia pestis Yersinia pseudotuberculosis
1.Fresh strains do not usually
ferment rhamnose
1. Fresh strains usually ferment
rhamnose
2. Do not ferment adonite 2. Ferment adonite with the
formation of acid
3. Do not ferment urea 3. Ferment urea
4. On desoxycholic citrate agar
they grow with the formation
of red colonies
4. On desoxycholic citrate agar
they grow with the formation
of yellow colonies
5. Are lysed by the plague
phage to the titre
5. Do not undergo lysis
17. Treatment and control
Fluid replacement therapy together with broad spectrum
antimicrobial treatment should be initiated promptly in young
animals.
A formalin-killed Y. pseudotuberculosis vaccine composed of
serotypes I, II and III, administered in two doses three weeks
apart has been shown to decrease the occurrence of clinical
disease in young deer.
StressfuI conditions should, where practicable, be minimized.
18. Yersinia pestis
• Gram negative rod with striking bipolar staining with special
stains
• Non-motile
• Grows as facultative anaerobe on many bacteriologic media
• Growth is more rapid in media containing blood or tissue fluids
and fastest at 30 C
• In cultures of blood agar at 37 C, colonies may be very small at
24 hours
• A virulent inoculum, derived from infected tissue, produces
gray and viscous colonies but after passage in the laboratory
the colonies become irregular and rough
• Has little biochemical activity, is somewhat variable
19. Antigenic structure
• All yersiniae possess lipopolysaccharides that have endotoxic
activity when released
• Produce many antigens and toxins that act as virulence factors
• The envelope contains a protein (fraction I) produced mainly at
37 C and confers antiphagocytic properties
• Virulent, wild-type Y. pestis carries V-W antigens, which are
encoded by genes on plasmids
• A 72-kb plasmid is essential for virulence
• Avirulent strains lack the plasmid
• Some stable avirulent strains have served as live vaccines
• Produces coagulase at 28 C (normal temperature of the flea)
but not at 35 C (transmission via fleas is low or absent in very
hot weather)
• Among several exotoxins produced, one is lethal for mice in
amounts of 1 µg - this homogenous protein (MW 74,000)
produces beta-adrenergic blockage and is cardiotoxic in animals
20. Pathogenesis and Pathology
When a flea feeds on a rodent infected with Y. pestis, the ingested
organisms multiply in the gut of the flea and helped by coagulase,
block its proventriculus so that no food can pass through
Subsequently the blocked and hungry flea bites ferociuosly and the
aspirated blood contaminated with Y. pestis from the flea, is
regurgitated into the bite wound
Inoculated organisms may be phagocytosed by polymorphonuclear
cells and monocytes
The organisms are killed by the polymorphonuclear cells but can
multiply in the monocytes because bacteria are multiplying at 37 C,
they produce antiphagocytic proteins (antiphagocytic protein capsule
fraction 1) and subsequently are able to resist phagocytosis
The pathogens rapidly reach the lymphatics and an intense
hemorrhagic inflammation develops in the enlarged lymph nodes,
may undergo necrosis and become fluctuant
Often reach bloodstream and become widely disseminated
Hemorrhagic and necrotic lesions may develop in all organs
Meningitis, pneumonia and serosanguineous pleuropericarditis are
prominent features
Primary pneumonic plague results from inhalation of infective drops
(from a coughing patient), with hemorrhagic consolidation, sepsis
and death
21. Yersinia pestis: Clinical Findings
• After an IP of 2 – 7 days,
there is high fever and
painful lymphadenopathy
commonly with greatly
enlarged, tender nodes
(buboes) in the groin or
axillae
• Vomiting and diarrhoea may
develop with early sepsis
• Later, DIC leads to
hypotension, altered mental
status, renal and cardiac
failure
• Terminally, signs of
pneumonia and meningitis
can appear
• Y. pestis multiplies
intravascularly and can be
seen in blood smears
The disease is transmitted by the bites of fleas
(e.g., Xenopsylla cheopis, the rat flea) which
have previously sucked blood from an
infected animal. The ingested bacilli
proliferate in the intestinal tract of the flea
and eventually block the lumen of the
proventriculus. The hungry flea, upon biting
another rodent, regurgitates into the wound a
mixture of plague bacilli and aspirated blood.
22. Clinical Diseases: Feline Plague
Cats usually acquire infection with Y. pestis by ingestion of infected rodents.
Three clinical forms of the disease are recognized: bubonic, septicaemic and
pneumonic.
The most common form of the disease is characterized by enlarged lymph
nodes (buboes) associated with lymphatic drainage from the site of
infection.
Affected superficial lymph nodes may rupture, discharging serosanguineous
fluid or pus.
Clinical signs include fever, depression and anorexia.
Septicaemia may occur without lymphadenopathy and is potentially fatal.
Pneumonic lesions may result from haematogenous spread.
Cats with pneumonic lesions are a potential source of human infection
through aerosol generation and should be euthanized.
Human infection can also be acquired through cat scratches and bites and
possibly through the bites of fleas from infected cats.
Care should be taken when handling infected animals
23. Diagnosis
Rapid recognition and lab confirmation of disease are essential
in order to institute lifesaving therapy
Plague should be suspected in febrile patients who have been
exposed to rodents in known endemic areas
Lymphadenopathy and severe depression in cats in endemic
areas may suggest feline plague.
Specimens from suspect cases should be sent to specialized
reference laboratories.
Suitable specimens include pus, blood and lymph node
aspirates.
Giemsa-stained smears may reveal large numbers of bipolar-
staining rods.
Direct fluorescent antibody tests are carried out in reference
laboratories.
A passive haemagglutination test, using Fraction 1 A antigen,
can be used on paired serum samples taken two weeks apart
from suspect cats - A substantial increase in the antibody level is
usually indicative of active infection.
24. Yersinia pestis: Diagnostic Lab Tests
Specimens
• Blood for culture
• Aspirates of enlarged lymph nodes for smear
and culture
• Acute and convalescent sera for antibody levels
• Sputum for culture
• CSF for smear and culture
Smears
• Examined after staining with Giemsa’s stain and
with specific immunofluorescent stains
• Definite identification is best done by
immunofluorescence
• With Wayson’s stain, may show striking bipolar
appearance
Culture
• On BA, MCA plates and in infusion broth
• Growth on solid media may be slow but blood
culture are often +ve in 24 hrs
• Tentatively identified by biochemical reactions
Serology
• In previously unvaccinated, a convalescent
serum antibody titre of 1:16 or greater is
presumptive evidence of infection
• A titre rise in two sequential specimens
confirms the serologic diagnosis
The Wayson stain is a
basic fuchsin-methylene
blue, ethyl alcohol-phenol
microscopic staining procedure.
It was originally a modified
methylene blue stain used for
diagnosing bubonic plague.[1]
With this stain, Yersinia
pestis appears purple with a
characteristic safety-pin
appearance,[2] which is due to
the presence of a central vacuole.
25. Treatment and control
Cats with suspected plague should be kept in isolation and
immediately treated for fleas to prevent those handling the
animal becoming exposed to flea bites.
The bubonic form of the disease may respond to parenterally
administered tetracyclines or chloramphenicol.
Multidrug resistance, mediated by a transferable plasmid, has
been reported recently in Y. pestis (Galimand et a!., 1997).
Unless promptly treated, have a mortality rate of about 50%;
pneumonic plague nearly 100%
Drug of choice is streptomycin
Tetracycline is an alternative drug and is sometimes given in
combination with streptomycin
In endemic areas, dogs and cats should be routinely treated for
fleas.
Rodent control measures should be implemented after flea
control procedures are in place.
26. 26
Yersinia Pestis: Epidemiology and Control
• Plague is an infection of wild rodents (field mice, gerbils, moles,
skunks, and other animals) that occurs in many parts of the world
• Chief enzootic areas are India, Southeast Asia (Vietnam), Africa, North
and South America
• The Western states of US and Mexico always contain reservoirs of
infection
• Epizootics with high mortality rates occur intermitently; at such times,
the infection can spread to domestic rodents (rats) and other animals
(cats) and humans can be infected by flea bites or by contact
• The commonest vector is the rat flea Xenopsylla cheopis but other
fleas may also transmit the infection
• Control requires surveys of infected animals, vectors and human
contacts
• All patients with suspected plague should be isolated particularly if
pulmonary involvement has not been ruled out
• All specimens must be treated with extreme caution
• Contacts of patients with suspected plague pneumonia should receive
tetracycline as chemoprophylaxis
• A formalin-killed vaccine is available for travelers to hyperendemic
areas and for persons at special high risk
27. Weaponization
• The CDC ranks the plague as a
Category A disease
– “Agents in Category A have the
greatest potential for adverse
public health impact with mass
casualties, and most require broad-
based public health preparedness
efforts (e.g., improved surveillance
and laboratory diagnosis and
stockpiling of specific medications).
– Category A agents also have a
moderate to high potential for
large-scale dissemination or a
heightened general public
awareness that could cause mass
public fear and civil disruption.”
28. Yersinia pestis as a Weapon
• Pros
• It is relatively easy to obtain
and mass produce.
• It can be delivered in aerosol
form
• Pneumonic plague causes a
rapid onset of illness with a
high fatality rate
• Pneumonic plague has a high
potential for secondary
spread of cases during an
epidemic
• 100-500 bacteria are enough
to cause pneumonic plague
• Cons
• Plague is fragile and dies
after about 1 hr
• Manufacturing an effective
weapon using Y. pestis would
require advanced knowledge
and technology
29. Additional Dangers of Yersinia pestis as a Weapon
• There is no currently available pre-exposure prophylaxis or
vaccine for plague
• Biological attack with plague might employ antimicrobial-
resistant strains that circumvent clinical efforts to deal with the
disease
– In 1995 a patient in Madagascar was found who had a Y.
pestis with a transferable multidrug resistance plasmid
(natural)
– Additionally, there are reports that the bioweapons
operations of the former Soviet Union engineered
multidrug resistant and fluoroquinolone resistant Y. pestis
30. Effectiveness of Y. pestis as a Weapon
• While antibiotic treatment of bubonic plague is usually effective,
pneumonic plague is difficult to treat and often results in death
regardless of treatment
• Most experts agree that “intentional dissemination of plague would
most probably occur via an aerosol of Y pestis, a mechanism that has
been shown to produce [pneumonic] disease in nonhuman
primates…The size of the outbreak would depend on the quantity of
biological agent used, characteristics of the strain, environmental
conditions, and methods of aerosilization…people would die quickly
following the onset of symptoms.” - JAMA May 3, 2000 Vol 283, No. 17
• In 1970, the WHO estimated that “if 50 kg of Y pestis were released as
an aerosol over a city of 5 million, plague could occur in as many as
150,000 persons, 36,000 of whom would be expected to die.” And this
does not take into account the people who would die from secondary
contraction of the disease.
80,000 to 100,000 hospitalized
500,000 secondary cases
Up to 100,000 deaths total
• According to the CDC, “The fatality rate of patients with pneumonic
plague when treatment is delayed more than 24 hours after symptom
onset is extremely high.”
32. Yersinia enterocolitica and Y. pseudotuberculosis
• Non-lactose fermenting Gram negative rods that are urease-
positive and oxidase negative
• Grow best at 25 C and are motile at 25 C but non-motile at 37 C
• Found in intestinal tract of a variety of animals in which they
cause disease and are transmissible to humans in whom they
can produce a variety of clinical syndromes
• Y. enterocolitica exists in >50 serotypes
• Most isolates from human disease belong to serotypes O3, O8
and O9
• There are striking geographic differences in the distribution of
Y. enterocolitica serotypes
• Y. pseudotuberculosis exists in at least 06 serotypes, but
serotypes O1 accounts for most human infections
33. Yersinia enterocolitica and Y. pseudotuberculosis
• Y. enterocolitica can produce a heat-stable enterotoxin but the
role of toxin in diarrhoea associated infection is not well
defined
• Y. enterocolitica has been isolated from rodents and domestic
animals and water contaminated by them
34. Transmission
• Transmission to humans occurs by contamination of food, drink
or fomites
• Y. pseudotuberculosis occurs in domestic and farm animals and
birds which excrete the organisms in feces
• Human infection probably results from ingestion of materials
contaminated with animal feces
• Person to person transmission with either of these organisms
is probably rare
35. Diagnostic Lab Tests:
Yersinia enterocolitica and Y. pseudotuberculosis
Specimens
• Stool, blood, or material obtained at surgical exploration
Culture
• Number in stool may be small and can be increased by cold
enrichment
• A small amount of feces or a rectal swab is placed in buffered
saline, pH 7.6, and kept at 4 C for 2-4 weeks; many fecal
organisms do not survive but Y. enterocolitica will multiply
• Subcultures made at intervals on MCA may yield yersiniae
36. Yersinia enterocolitica and Y. pseudotuberculosis
Serology
• In paired serum specimens taken 2 or more weeks apart, a rise in
agglutinating antibodies can be shown
• However, cross reactions between yersiniae and other organisms
such as vibrios, salmonellae, brucellae may confuse the results
37. Treatment:
Yersinia enterocolitica and Y. pseudotuberculosis
• Most yersinia infections with diarrhoea are self-limited
• Y. enterocolitica is generally susceptible to aminoglycosides,
chloramphenicol, tetracycline, trimethoprim-
sulphamethoxazole, piperacillin, 3rd generation cephalosporins
and fluoroquinolones.
• Typically resistant to ampicillin and 1st generation
cephalosporins
• Proved yersinia sepsis or meningitis has a high mortality rate
but deaths occur mainly in immunocompromised patients
• Yersinia sepsis can be successfully treated with 3rd generation
cephalosporins possibly in combination with aminoglycosides
or a fluoroquinolone possibly with another antimicrobial
38. Prevention and Control:
Yersinia enterocolitica and Y. pseudotuberculosis
• Contact with farm and domestic animals, their feces or
materials contaminated by them probably accounts for most
human infections
• Meat and dairy products have occasionally been indicated as
sources of infection, and group outbreaks have been traced to
contaminated food or drink
• Conventional sanitary precautions are probably helpful
39. Thanks
Acknowledgement: All the material/presentations available online on the subject
are duly acknowledged.
Disclaimer: The author bear no responsibility with regard to the source and
authenticity of the content.
Questions???